X-ray tube.



F. J. FARRELLY & A. GREINER.

X-R AY TUBE. v APPLICATION FILED ]AN.25,1916.

1,276,196. P3t611t6dAl1g-2Q 1918.

WITNESSES: A n I INAVENTORS.

A i M 16 A TTORNE Y.

FRANCIS J. AND ALFRED GBEINER, 0F HARTFORD, CONNECTICUT.

X' -BAY TUBE.

l speci fication of Letters Patent. Patented Aug. 2c, 1918.

Application filed January 25, 1916,. Serial No. 74,134.

To all whom, it may concern:

Be it known that we, FRANCIS J. FAR-s a break of the glass bulb at the point where the cathode neck joins the bulb.

In the drawings-- Figure 1 is a side view of an X-ray tube equipped with our invention.

Fig. 2 is a sectional View of the cathode end of the tube on an enlarged scale.

Referring to the drawings, a denotes the main bulb, b the cathode neck, and c the anode neck; 11 is the anode, e the cathode, surrounded by a metallic sleeve 5 out of electrical connection therewith, said sleeve being supported from the walls ofthe cathode neck by projections 6 therefrom entering depressions or apertures 7 in the sleeve.

10 denotes the cathode stem embedded in insulating material, indicated here as lass 11, on the outside of which there is tted a metallic covering 12 in the form of a tube of proper meta-has aluminum. These three parts, the stem, insulation, and metallic tube, are fitted rather closely together, and the tube 12 is not in electricalcontact with the cathode e or the stem 10. 15 denotes the cathode neck as at 21, adjacent'to the terminal 15. This forms a conductive path for any electrical manifestations which build up or accumulate within the cathode neck, permitting them to escape outside the tube and discharge over onto the terminal 15. This causes to a large extent the dissipation of electrical manifestations within the oathode neck, and the sleeve 5 protects the wall of the cathode neck against a concentrated bombardment of any electrical manifestations which are not discharged on the exterior of the tube.

As a result of this construction it has been found that tubes equipped with this invention operate with'great steadiness, and that the overheating of the cathodeneck is very largely eliminated, at least overheating to such an extent as might cause the cracking of the tube at this point. The best results have been attained by the combined use of in said stem, a metallic member carried by said shield, and a conductor from said metallic member leading to the exterior of said tube and into cooperative relationship with said exteriorterminal.

2. In an X-ray tube a cathode stem supporting a cathode, a covering of electrically insulating-material on said stem, a metallic member carried by said covering out of electrical contact with said cathode and stem, and a conductor from said metallic member leading to the exterior of said,tube and into cooperative relationship with said exterior terminal.

FRANCIS J. FARRELLY. ALFRED GBEINER. 

